42 









LIBELLULA DEPRESSA. THE FLAT BLUE-TAILED LIBELLULA. 



Plate XXVI. fig. k-m. 



Synonyms. Libellula depressa, Linn. Syst. Nat. ii. p. 932. Donovan Brit. Ins. vol. i. pi. 24. $ . 

 vol. iii. pi. 81. $. vol. ii. pi. 44. Larva. 



The immature insect is found in foul ditches and stagnant waters, of different sizes, any time 

 in the year; it is of a dark muddy colour. When full fed and ready to undergo its transformation 

 to the winged state, it appears as a pupa at (£); it then crawls up out of the water by the help of 

 a stone, stick, or piece of grass, where, holding fast by the legs, the skin on the back splits or 

 bursts, and the libelulla draws itself gently out, as at (/); it then holds by the legs, with its wings 

 hanging downwards, where they gradually stretch and dry, and are quickly fit for flight. The 

 libellula at (n) is of a different kind, (Libellula cancellata, Linn. ? Syst. Nat. ii. p. 902. Donov. 

 Brit. Ins. 14. pi. 472.) although by some it has been mistaken for the male to the blue-tailed. 

 But it is a mistake, the blue-tail being the male, the female of which has a flat brown tail. 1 have 

 given an exact drawing of the male at (m). 



Expansion of the wings three inches. 



The remarkable difference existing between the appearance of the larva and 

 perfect states of this tribe of insects, is equalled by that of the element in which they 

 reside at these different periods of existence, as well as by the difference in their 

 motions ; the larva being a slow inactive creature, and the imago one of the most 

 agile of the insect race. In all their states they are formed for rapine ; and the 

 hawk-like motions of the fly chasing minute insects, upon which it subsists in the 

 air, are very elegant. In all its states, however, it is beautifully adapted in its 

 organization for its mode of life : the larva, slow and hideous, has need of an 

 instrument enabling it to obtain its prey with adroitness ; and the singular construc- 

 tion of the organs of its mouth, some of which are transformed into a large mask with 

 a pair of hooks, capable of being extended at will to a considerable distance in front 

 of the body, has attracted the attention of most Entomologists. The general struc- 

 ture of the perfect insect is not less beautifully adapted for the performance of its 

 habits. " Observe the Dragon Fly, the emperor of his tribe, his wings rustle as he 

 hovers stationary and hawk-like in the air ; his appetite is insatiable ; his food the 

 active occupants of his own element ; it is given to him in charge to set bounds to 

 the increase of the insect race ; he beholds his prey afar off; he darts on it like the 

 rapidity of a lightning flash ; to devour it ere life is departed is the work of an 

 instant ; he sails round and round ; he soars up and down ; when the sky is serene, 

 he seeks his prey, like the swallows, almost beyond the reach of human sight. 

 What organs does such an animal require ? Are they not these, — eyes, mouth, and 

 wings? How has nature provided for his wants ? Regard his. head — below, it is 

 all mouth ; above, it is one continuous eye. Contemplate his wings — their character 

 is strength and lightness, power and activity. His body is slender and graceful ; 

 like a rudder, it serves as an instrument wherewith to shape his course. Porrected 

 feelers, whether cranial, labial, or maxillary, would be comparatively useless to an 

 animal whose dependence for support is on the keenness of its vision and the velocity 



